The use of methane-producing anaerobic biological reactors (MPABRs), such as anaerobic digestion, is particularly attractive for treating high-strength organic wastes as it produces a methane-rich biogas, does not require any external supply of oxygen (as with aerobic treatment) and produces only a small amount of sludge. In spite of these advantages, industry is often hesitant to use MPABRs for treating high-strength industrial wastewaters due to its susceptibility to pH change and heavy metal toxicity.